Add react-scripts version compatibility for monorepos. (facebook#3953)

Author: bradfordlemley

packages/react-scripts/template/README.md

@@ -1821,6 +1821,9 @@ Learn more about React Styleguidist:
 * [Documentation](https://react-styleguidist.js.org/docs/getting-started.html)
 
 ## Sharing Components in a Monorepo
+
+>Note: this feature is available with `react-scripts@2.0.0` and higher.
+
 A typical monorepo folder structure looks like this:
 ```
 monorepo/